1. The Field of the Invention
The present invention is in the field of shaped, flexible dental trays and strips used to deliver a dental bleaching composition to a person's teeth. More particularly, the invention relates to flexible dental trays and strips with enhanced user comfort and tooth adhesion.
2. The Relevant Technology
Virtually all people desire white or whiter teeth. A common bleaching method involves the use of a dental tray that is custom-fitted to a person's teeth and that is therefore relatively comfortable to wear. One type of customized tray is made by vacuum forming a sheet of moisture resistant thermoplastic polymer material over a stone cast of a person's teeth, after which the custom tray may be cut out. Another is customized directly using a person's teeth as a template (e.g., “boil-and-bite” trays). Non-customized trays that approximate the shapes and sizes of a variety of users' dental arches have also been used. A dental bleaching composition is placed into the tray and the tray placed over the person's teeth for a desired period of time.
Another tooth bleaching method involves placing a flexible bleaching strip over a user's tooth surfaces. Conventional bleaching strips comprise a flexible plastic strip coated with a dental bleaching gel of moderate viscosity and relatively low stickiness on the side of the strip facing the user's teeth. To install the bleaching strip, a portion of the bleaching strip is placed over the front surfaces of the user's teeth, and the remainder is folded around the occlusal edges of the teeth and against a portion of the lingual surfaces.
Because of the generally poor adhesion of bleaching strips to the user's teeth, coupled with their generally flimsy nature, it is often difficult for the user to maintain the bleaching strip in its proper position for the recommended time. Conventional bleaching strips are prone to slip off the teeth as a result of even minimal movement of the user's mouth, jaw or tongue. It is recommended that the user not eat, drink, smoke or sleep while wearing the bleaching strip. In some cases, the bleaching strip can become so dislodged or mangled that it must be removed by the user and replaced with a fresh bleaching strip to complete the recommended bleaching time.
Ultimately, the main impediment to successful bleaching is the failure of users to complete the prescribed bleaching regimen. If the bleaching apparatus is difficult to install over a person's teeth, requires numerous repetitions to achieve observable results, and/or is uncomfortable to wear, the user may simply give up and prematurely abort the prescribed bleaching regimen. Thus, even if dental bleaching is possible using a particular bleaching apparatus or method, it is less likely to occur if the inadequacies of the bleaching apparatus or method cause a user to become discouraged before desired results are attained.